Born to run: testing cosmological inflation with large-scale extragalactic surveys
Speaker: David Parkinson
Affiliation: Korea Astronomy and Space Science Institute
Abstract
The model of cosmological slow-roll inflation predicts a spectrum of density perturbations in the early Universe, which seed the initial gravitational instabilities that generate the distribution of matter observed today. This power spectrum is predicted to have a spectral index close to one and very small running of that index (10^-3). Inflation also predicts a spectrum of primordial gravitational waves. While the density fluctuations have been measured by the cosmic microwave background and large-scale surveys, and the spectral index has been confirmed to be close to unity, the imprint of primordial gravitational waves have not yet been detected in the CMB polarisation. Here I show that if the upper limit on the gravitational wave amplitude is further reduced, but no detection is made, then slow-roll inflation generically predicts a larger running of the density power spectrum. This running is an alternative probe of the early universe, and the inflationary prediction will be detectable by a combination of future all-sky surveys such as DESI, SPHEREx and CHIME, by 2030.
About Physics Seminars
The weekly Physics Seminar series focuses on a broad range of physics research within SMP, along with frequent presentations from visiting researchers. Seminars are usually scheduled for 1.00pm on Tuesdays.
The talks are typically more specialised than a colloquium but are often attended by staff and PhD students across a broad range of areas. Speakers are thus encouraged to include introductory material in the talks.
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